Introduction: Hippocampal differentiation

The hippocampus shows a long axis anterior-posterior differentiation of function
Poppenk et al. (2013) suggested that the type of processing in the hippocampus varied from fine to coarse grained in a posterior to anterior direction, based on evidence that receptive fields vary from narrow at the posterior end of the hippocampus to broad at the anterior end (Kjelstrup et al., 2008; Maurer Vanrhoads, Sutherland, Lipa, & McNaughton, 2005).
Anterior = pattern completion, posterior = pattern separation

Grady et al., 2020

- The anterior and posterior portions may undergo different developmental trajectories across the lifespan, and may give rise to some of the cognitive changes that commonly accompany the aging process (i.e., episodic memory)

Langnes et al., 2020

## Sleep and the hippocampus

Hippocampus involved in sleep architecture (theta in REM, sharp wave ripples in NREM, coupling with slow wave)
Chronic sleep disruption and circadian rhythmicity affect hippocampal neurogenesis in animals (Raven et al., 2018; Kreutzmann et al., 2015)
In older adults, more robust rest-activity rhythms were associated with greater anterior hippocampal volume (Sherman et al., 2015)
Sleep disturbance in older adults predicts increasingly worse scores on standardized neuropsychological tests, including memory subcomponents that depend upon the hippocampus (HVLT)

Research Question

Are sleep-wake patterns associated with volumetric differences along the hippocampal long axis that underlie episodic memory?

Methods

Healthy younger (n = 43, age = 21.5, ±3.86) and older (n = 43, age = 68.2, ±5.63) adults
Actigraphy
fMRI scanning
Episodic memory measures: associative memory task, CVLT (older adults only)
Working memory/novelty measure: repeat task

Actigraphy

Selected mean sleep duration, acrophase, amplitude, and interdaily stability as measures of interest

- Planned to use CVLT, but did not have data available from younger adults :(

CVLT

Associative memory task

Had associative memory task data, but really only have a good measure of intial encoding and short-term recall (no long-term recall measure)
This is problematic because really wanted long-term recall measure (Langnes et al. 2020)

Repeat task

1-back working memory task
Novelty vs. familiarity

Participants

	Young Adults	Older Adults
n	43	55
Group = Older Adults (%)	0 ( 0.0)	55 (100.0)
age (mean (SD))	21.51 (3.86)	68.20 (5.63)
sex = Male (%)	17 (39.5)	12 ( 21.8)
years_educ (mean (SD))	14.62 (2.38)	16.88 (2.94)
global_psqi (mean (SD))	4.21 (1.79)	4.40 (2.15)
cesd_score (mean (SD))	7.00 (4.08)	2.00 (NA)
gds_total (mean (SD))	0.00 (0.00)	1.20 (2.30)
sleep_time_mean_sleep (mean (SD))	398.57 (97.86)	404.55 (85.83)
efficiency_mean_sleep (mean (SD))	81.43 (6.92)	80.62 (9.04)
total_ac_mean_active (mean (SD))	326940.99 (189192.81)	251197.38 (89924.99)
actamp (mean (SD))	1.61 (0.29)	1.58 (0.34)
IS (mean (SD))	0.42 (0.11)	0.54 (0.12)
actphi (mean (SD))	16.38 (1.45)	14.73 (1.65)

Parcellation

Used brainlife.io to obtain hippocampal volume measures
Uploaded BIDS dataset

$brainlife.io$ - Checked orientation of all T1 images - Ran ACPC alignment

Originial T1:

ACPC aligned:

ACPC alignment

Used “HBT” divisions (Iglesias et al., 2015)
This parcellation was based on both ex vivo and in vivo data

Manual labelling

In vivo segmentation

Hippocampal parcellation

Results

Aging and hippocampal volume

ICV normalized

We wanted to look at hippocampal volume independently of total intracranial volume, so we calculated HC volume as follows: adjusted HC volume = raw HC volume – b X (ICV – average ICV), where b is the slope of regression of the raw HC volume on ICV (Brehmer et al., 2020).

Memory Performance

	Young Adults	Older Adults
n	43	52
Group = Older Adults (%)	0 (0.0)	52 (100.0)
cvlt_sdelay_recall_zscore (mean (SD))	NaN (NA)	0.64 (1.03)
cvlt_ldelay_recall_zscore (mean (SD))	NaN (NA)	0.54 (0.95)
cvlt_recognition_hits_zscore (mean (SD))	NaN (NA)	-0.14 (1.00)
cvlt_recognition_fp_zscore (mean (SD))	NaN (NA)	-0.17 (0.96)
cvlt_zscore (mean (SD))	NaN (NA)	0.27 (0.73)
acc_mean.learning (mean (SD))	0.88 (0.16)	0.80 (0.17)
acc_std.learning (mean (SD))	0.24 (0.16)	0.34 (0.14)
rt_c_mean.learning (mean (SD))	1732.99 (401.86)	2770.81 (1688.63)
rt_c_std.learning (mean (SD))	739.88 (288.11)	1388.35 (1623.11)
acc_mean.test (mean (SD))	0.90 (0.11)	0.84 (0.10)
acc_std.test (mean (SD))	0.24 (0.16)	0.33 (0.13)
rt_c_mean.test (mean (SD))	2459.76 (211.57)	2773.37 (225.69)
rt_c_std.test (mean (SD))	342.31 (141.26)	450.80 (107.35)

##   record_id acc_mean.learning acc_mean.test
## 1     40550              0.25     0.6666667

Hippocampal volume and CVLT performance within older adults

Only had CVLT data for older adults
Did not see relationship between hippocampal volume and CVLT memory

Sleep and CVLT performance

Hippocampal volume and associative memory task performance

Using the associative memory task allowed us to include the young adult comparison group.
There was a significant Group by hippocampal head volume effect on associative memory accuracy during the test phase, where older adults showed a positive association between hippocampal head volume and memory accuracy, whereas young adults showed the opposite trend.

Sleep and memory performance

In this study, young and older adult age groups showed differential relationships between acrophase and (1) accuracy during the test phase, and (2) response time on correct trials during both the learning and test phases

Hippocampal volume and sleep

Nada!

Discussion

Did not identify evidence of a long-axis encoding/retrieval differentiation using either of our episodic memory tasks
Among older adults, greater hippocampal head volume was associated with greater associative memory accuracy during test.
Acrophase was also associated with greater associative memory accuracy during test, consistent with (Ming Yi Lee et al., 2021) which recently found that older adults with delayed acrophase were less likely to have better cognition
But, acrophase was not associated with hippocampal head volume
No other selected sleep measures (mean sleep duration, rhythm amplitude, interdaily stability, acrophase) were associated with hippocampal volume at conventional statistical thresholds.
Did not see any relationship with CVLT performance in contrast to prior literature.

Limitations

Lack of CVLT-II data for young adult group prevented examination of different components of memory across adult development
Hoped to partially overcome this limitation by evaluating relationships between hippocampal volume and aspects of performance on an associative memory task. This task provided behavioral measures much narrower in scope compared to the CVLT-II, with instead only measures of initial encoding and short-term recall.
Participants across both age groups performed well on this task, making it difficult to tease out functional variability.
Healthy group not representative of “normal” aging
Cross-sectional nature of the study may have prevented us from picking up on the key features of sleep that are important markers of cognitive health. Maybe the trajectories of these sleep patterns rather than their raw values are more revealing about the expected status of an individual’s cognitive performance and underlying brain health.

All analyses below

Hippocampal volume and associative memory

Excluded participants below chance accuracy

Sleep

Sleep and hippocampal volume

Sleep and cognition

Stats

## 
## Call:
## lm(formula = acc_mean.learning ~ Hippocampal_head * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.51771 -0.03858  0.03792  0.08202  0.17520 
## 
## Coefficients:
##                                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                         1.204e+00  2.704e-01   4.452 2.73e-05 ***
## Hippocampal_head                   -8.901e-05  7.792e-05  -1.142    0.257    
## GroupOlder Adults                  -5.322e-01  3.668e-01  -1.451    0.151    
## Hippocampal_head:GroupOlder Adults  1.408e-04  1.099e-04   1.281    0.204    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1396 on 80 degrees of freedom
## Multiple R-squared:  0.06475,    Adjusted R-squared:  0.02968 
## F-statistic: 1.846 on 3 and 80 DF,  p-value: 0.1454

## 
## Call:
## lm(formula = acc_mean.learning ~ Hippocampal_head + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.55334 -0.03241  0.03999  0.08152  0.16358 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        9.588e-01  1.920e-01   4.994 3.34e-06 ***
## Hippocampal_head  -1.820e-05  5.514e-05  -0.330   0.7423    
## GroupOlder Adults -6.425e-02  3.403e-02  -1.888   0.0626 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1401 on 81 degrees of freedom
## Multiple R-squared:  0.04556,    Adjusted R-squared:  0.022 
## F-statistic: 1.933 on 2 and 81 DF,  p-value: 0.1513

## 
## Call:
## lm(formula = rt_c_mean.learning ~ Hippocampal_head * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1451.0  -426.1  -103.2   334.6  3802.2 
## 
## Coefficients:
##                                     Estimate Std. Error t value Pr(>|t|)
## (Intercept)                        1370.1497  1428.7625   0.959    0.340
## Hippocampal_head                      0.1008     0.4117   0.245    0.807
## GroupOlder Adults                   424.4801  1938.0878   0.219    0.827
## Hippocampal_head:GroupOlder Adults    0.1022     0.5805   0.176    0.861
## 
## Residual standard error: 737.5 on 80 degrees of freedom
## Multiple R-squared:  0.2037, Adjusted R-squared:  0.1738 
## F-statistic:  6.82 on 3 and 80 DF,  p-value: 0.0003762

## 
## Call:
## lm(formula = rt_c_mean.learning ~ Hippocampal_head + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1461.8  -429.9  -100.4   346.9  3818.0 
## 
## Coefficients:
##                    Estimate Std. Error t value Pr(>|t|)    
## (Intercept)       1192.2553  1004.4516   1.187    0.239    
## Hippocampal_head     0.1522     0.2885   0.528    0.599    
## GroupOlder Adults  764.3598   178.0484   4.293 4.85e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 733.1 on 81 degrees of freedom
## Multiple R-squared:  0.2033, Adjusted R-squared:  0.1837 
## F-statistic: 10.34 on 2 and 81 DF,  p-value: 0.0001003

## 
## Call:
## lm(formula = acc_mean.learning ~ Hippocampal_tail * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.56035 -0.03390  0.04314  0.08288  0.16729 
## 
## Coefficients:
##                                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                         8.706e-01  2.281e-01   3.817 0.000265 ***
## Hippocampal_tail                    2.147e-05  1.933e-04   0.111 0.911854    
## GroupOlder Adults                   1.699e-02  3.109e-01   0.055 0.956560    
## Hippocampal_tail:GroupOlder Adults -6.851e-05  2.735e-04  -0.250 0.802844    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.141 on 80 degrees of freedom
## Multiple R-squared:  0.04513,    Adjusted R-squared:  0.009327 
## F-statistic:  1.26 on 3 and 80 DF,  p-value: 0.2936

## 
## Call:
## lm(formula = acc_mean.learning ~ Hippocampal_tail + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.56378 -0.03264  0.04813  0.08091  0.16454 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        9.108e-01  1.612e-01   5.651  2.3e-07 ***
## Hippocampal_tail  -1.276e-05  1.359e-04  -0.094   0.9254    
## GroupOlder Adults -6.046e-02  3.286e-02  -1.840   0.0694 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1402 on 81 degrees of freedom
## Multiple R-squared:  0.04439,    Adjusted R-squared:  0.02079 
## F-statistic: 1.881 on 2 and 81 DF,  p-value: 0.159

## 
## Call:
## lm(formula = rt_c_mean.learning ~ Hippocampal_tail * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1524.6  -403.4   -85.8   311.4  3906.8 
## 
## Coefficients:
##                                     Estimate Std. Error t value Pr(>|t|)
## (Intercept)                        1232.1159  1192.3848   1.033    0.305
## Hippocampal_tail                      0.4144     1.0105   0.410    0.683
## GroupOlder Adults                  1699.4404  1625.4811   1.045    0.299
## Hippocampal_tail:GroupOlder Adults   -0.8648     1.4296  -0.605    0.547
## 
## Residual standard error: 737.2 on 80 degrees of freedom
## Multiple R-squared:  0.2043, Adjusted R-squared:  0.1744 
## F-statistic: 6.845 on 3 and 80 DF,  p-value: 0.0003655

## 
## Call:
## lm(formula = rt_c_mean.learning ~ Hippocampal_tail + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1495.2  -415.6   -78.3   315.9  3867.1 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)    
## (Intercept)       1739.50446  844.13529   2.061   0.0425 *  
## Hippocampal_tail    -0.01769    0.71201  -0.025   0.9802    
## GroupOlder Adults  721.76536  172.08137   4.194 6.95e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 734.3 on 81 degrees of freedom
## Multiple R-squared:  0.2006, Adjusted R-squared:  0.1809 
## F-statistic: 10.16 on 2 and 81 DF,  p-value: 0.0001152

## 
## Call:
## lm(formula = acc_mean.test ~ Hippocampal_head * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.22040 -0.07173  0.01559  0.07299  0.15640 
## 
## Coefficients:
##                                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                         1.142e+00  1.844e-01   6.192 2.41e-08 ***
## Hippocampal_head                   -6.827e-05  5.315e-05  -1.284   0.2027    
## GroupOlder Adults                  -5.673e-01  2.502e-01  -2.268   0.0260 *  
## Hippocampal_head:GroupOlder Adults  1.541e-04  7.493e-05   2.057   0.0429 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.0952 on 80 degrees of freedom
## Multiple R-squared:  0.1296, Adjusted R-squared:  0.09698 
## F-statistic: 3.971 on 3 and 80 DF,  p-value: 0.01082

## 
## Call:
## lm(formula = acc_mean.test ~ Hippocampal_head + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.24185 -0.06762  0.01380  0.06941  0.15168 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        8.738e-01  1.330e-01   6.569 4.52e-09 ***
## Hippocampal_head   9.277e-06  3.820e-05   0.243   0.8088    
## GroupOlder Adults -5.492e-02  2.358e-02  -2.329   0.0224 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09708 on 81 degrees of freedom
## Multiple R-squared:  0.08358,    Adjusted R-squared:  0.06096 
## F-statistic: 3.694 on 2 and 81 DF,  p-value: 0.02916

## 
## Call:
## lm(formula = rt_c_mean.test ~ Hippocampal_head * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -417.59 -137.50   -1.05  114.96  612.22 
## 
## Coefficients:
##                                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                        2250.14650  400.73076   5.615 2.75e-07 ***
## Hippocampal_head                      0.05575    0.11548   0.483    0.631    
## GroupOlder Adults                   410.94354  543.58326   0.756    0.452    
## Hippocampal_head:GroupOlder Adults   -0.02296    0.16281  -0.141    0.888    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 206.9 on 80 degrees of freedom
## Multiple R-squared:  0.3907, Adjusted R-squared:  0.3679 
## F-statistic:  17.1 on 3 and 80 DF,  p-value: 1.131e-08

## 
## Call:
## lm(formula = rt_c_mean.test ~ Hippocampal_head + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -417.38 -139.36   -3.32  116.35  613.50 
## 
## Coefficients:
##                    Estimate Std. Error t value Pr(>|t|)    
## (Intercept)       2.290e+03  2.817e+02   8.129 4.17e-12 ***
## Hippocampal_head  4.420e-02  8.091e-02   0.546    0.586    
## GroupOlder Adults 3.346e+02  4.993e+01   6.701 2.53e-09 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 205.6 on 81 degrees of freedom
## Multiple R-squared:  0.3906, Adjusted R-squared:  0.3755 
## F-statistic: 25.96 on 2 and 81 DF,  p-value: 1.945e-09

## 
## Call:
## lm(formula = acc_mean.test ~ Hippocampal_tail * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.23819 -0.05677  0.02205  0.06771  0.17914 
## 
## Coefficients:
##                                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                         8.767e-01  1.568e-01   5.591 3.03e-07 ***
## Hippocampal_tail                    2.483e-05  1.329e-04   0.187    0.852    
## GroupOlder Adults                  -1.893e-01  2.138e-01  -0.886    0.379    
## Hippocampal_tail:GroupOlder Adults  1.233e-04  1.880e-04   0.656    0.514    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09695 on 80 degrees of freedom
## Multiple R-squared:  0.09732,    Adjusted R-squared:  0.06346 
## F-statistic: 2.875 on 3 and 80 DF,  p-value: 0.04128

## 
## Call:
## lm(formula = acc_mean.test ~ Hippocampal_tail + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.23559 -0.05522  0.01669  0.07115  0.16763 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        8.044e-01  1.111e-01   7.243 2.28e-10 ***
## Hippocampal_tail   8.645e-05  9.367e-05   0.923   0.3588    
## GroupOlder Adults -4.986e-02  2.264e-02  -2.202   0.0305 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09661 on 81 degrees of freedom
## Multiple R-squared:  0.09246,    Adjusted R-squared:  0.07005 
## F-statistic: 4.126 on 2 and 81 DF,  p-value: 0.01966

## 
## Call:
## lm(formula = rt_c_mean.test ~ Hippocampal_tail * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -420.20 -123.31  -14.39  112.82  611.27 
## 
## Coefficients:
##                                     Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                        1897.2309   329.3795   5.760  1.5e-07 ***
## Hippocampal_tail                      0.4647     0.2791   1.665   0.0999 .  
## GroupOlder Adults                   958.8544   449.0163   2.135   0.0358 *  
## Hippocampal_tail:GroupOlder Adults   -0.5479     0.3949  -1.387   0.1692    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 203.7 on 80 degrees of freedom
## Multiple R-squared:  0.4095, Adjusted R-squared:  0.3873 
## F-statistic: 18.49 on 3 and 80 DF,  p-value: 3.32e-09

## 
## Call:
## lm(formula = rt_c_mean.test ~ Hippocampal_tail + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -418.57 -138.53  -24.57  109.54  602.28 
## 
## Coefficients:
##                    Estimate Std. Error t value Pr(>|t|)    
## (Intercept)       2218.7149   235.4315   9.424 1.15e-14 ***
## Hippocampal_tail     0.1910     0.1986   0.962    0.339    
## GroupOlder Adults  339.3944    47.9939   7.072 4.90e-10 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 204.8 on 81 degrees of freedom
## Multiple R-squared:  0.3952, Adjusted R-squared:  0.3803 
## F-statistic: 26.47 on 2 and 81 DF,  p-value: 1.425e-09

## 
## Call:
## lm(formula = Hippocampal_head ~ sleep_time_mean_sleep + Group, 
##     data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -708.92 -138.10    0.67  181.29  570.04 
## 
## Coefficients:
##                         Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           3474.52100  167.08274  20.795  < 2e-16 ***
## sleep_time_mean_sleep   -0.04161    0.41703  -0.100    0.921    
## GroupOlder Adults     -268.94030   62.08466  -4.332 4.21e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 282.3 on 81 degrees of freedom
## Multiple R-squared:  0.191,  Adjusted R-squared:  0.171 
## F-statistic: 9.561 on 2 and 81 DF,  p-value: 0.0001871

## 
## Call:
## lm(formula = Hippocampal_tail ~ sleep_time_mean_sleep + Group, 
##     data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -351.11  -55.08   11.93   72.01  270.93 
## 
## Coefficients:
##                        Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           1116.0215    67.4855  16.537  < 2e-16 ***
## sleep_time_mean_sleep    0.1510     0.1684   0.896 0.372812    
## GroupOlder Adults      -89.9853    25.0763  -3.588 0.000568 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 114 on 81 degrees of freedom
## Multiple R-squared:  0.1394, Adjusted R-squared:  0.1181 
## F-statistic: 6.558 on 2 and 81 DF,  p-value: 0.002291

## 
## Call:
## lm(formula = Hippocampal_tail ~ actphi * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -324.89  -49.89    0.72   67.34  286.91 
## 
## Coefficients:
##                          Estimate Std. Error t value Pr(>|t|)    
## (Intercept)              1222.202    204.501   5.976 6.44e-08 ***
## actphi                     -3.339     12.481  -0.268    0.790    
## GroupOlder Adults        -435.455    271.720  -1.603    0.113    
## actphi:GroupOlder Adults   23.961     17.480   1.371    0.174    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 112.9 on 78 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.1463, Adjusted R-squared:  0.1135 
## F-statistic: 4.456 on 3 and 78 DF,  p-value: 0.006083

## 
## Call:
## lm(formula = Hippocampal_head ~ actphi + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -707.66 -147.58  -11.57  182.13  567.19 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)       3579.604    363.290   9.853 2.12e-15 ***
## actphi              -7.699     22.081  -0.349 0.728281    
## GroupOlder Adults -278.751     74.213  -3.756 0.000329 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 285.2 on 79 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.1834, Adjusted R-squared:  0.1628 
## F-statistic: 8.873 on 2 and 79 DF,  p-value: 0.0003339

## 
## Call:
## lm(formula = Hippocampal_tail ~ actphi + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -334.17  -53.61    0.11   64.75  278.50 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)       1022.836    144.563   7.075 5.36e-10 ***
## actphi               8.878      8.787   1.010   0.3154    
## GroupOlder Adults  -65.165     29.532  -2.207   0.0302 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 113.5 on 79 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.1258, Adjusted R-squared:  0.1036 
## F-statistic: 5.682 on 2 and 79 DF,  p-value: 0.004949

## 
## Call:
## lm(formula = Hippocampal_head ~ IS + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -750.57 -143.71  -19.09  204.23  527.53 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        3347.92     128.07  26.141  < 2e-16 ***
## IS                  286.41     281.95   1.016    0.313    
## GroupOlder Adults  -321.52      72.91  -4.410 3.55e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 282.7 on 72 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.2218, Adjusted R-squared:  0.2001 
## F-statistic: 10.26 on 2 and 72 DF,  p-value: 0.0001202

## 
## Call:
## lm(formula = Hippocampal_tail ~ IS + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -283.81  -66.85   12.38   88.11  239.18 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        1075.86      52.78  20.385  < 2e-16 ***
## IS                  221.43     116.19   1.906 0.060673 .  
## GroupOlder Adults  -106.15      30.05  -3.533 0.000722 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 116.5 on 72 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.1493, Adjusted R-squared:  0.1256 
## F-statistic: 6.316 on 2 and 72 DF,  p-value: 0.00297

## 
## Call:
## lm(formula = cvlt_1 ~ sleep_time_mean_sleep + age, data = filter(dmem2, 
##     Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.5170 -0.8654  0.2169  0.9648  2.3303 
## 
## Coefficients:
##                        Estimate Std. Error t value Pr(>|t|)   
## (Intercept)            8.960868   2.965868   3.021  0.00437 **
## sleep_time_mean_sleep  0.004266   0.002506   1.702  0.09650 . 
## age                   -0.063447   0.040510  -1.566  0.12518   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.407 on 40 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.1209, Adjusted R-squared:  0.07698 
## F-statistic: 2.751 on 2 and 40 DF,  p-value: 0.07593

## 
## Call:
## lm(formula = cvlt_sdelay_recall ~ sleep_time_mean_sleep + age, 
##     data = filter(dmem2, Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -6.5870 -2.0318  0.4958  2.0471  4.9189 
## 
## Coefficients:
##                        Estimate Std. Error t value Pr(>|t|)  
## (Intercept)           15.331804   6.386172   2.401   0.0211 *
## sleep_time_mean_sleep  0.010611   0.005396   1.966   0.0562 .
## age                   -0.123029   0.087228  -1.410   0.1661  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 3.029 on 40 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.1307, Adjusted R-squared:  0.08725 
## F-statistic: 3.007 on 2 and 40 DF,  p-value: 0.06071

## 
## Call:
## lm(formula = cvlt_ldelay_recall ~ sleep_time_mean_sleep + age, 
##     data = filter(dmem2, Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -8.6033 -1.6688  0.4091  1.6829  4.7386 
## 
## Coefficients:
##                        Estimate Std. Error t value Pr(>|t|)   
## (Intercept)           16.680939   6.106533   2.732  0.00933 **
## sleep_time_mean_sleep  0.006696   0.005160   1.298  0.20186   
## age                   -0.115868   0.083408  -1.389  0.17247   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 2.896 on 40 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.08502,    Adjusted R-squared:  0.03927 
## F-statistic: 1.858 on 2 and 40 DF,  p-value: 0.1691

## 
## Call:
## lm(formula = cvlt_recognition_hits ~ sleep_time_mean_sleep + 
##     age, data = filter(dmem2, Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.8920 -0.6978  0.1086  0.9122  1.6265 
## 
## Coefficients:
##                         Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           17.9055295  2.6833891   6.673 5.37e-08 ***
## sleep_time_mean_sleep  0.0006457  0.0022675   0.285    0.777    
## age                   -0.0490041  0.0366521  -1.337    0.189    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.273 on 40 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.04515,    Adjusted R-squared:  -0.002594 
## F-statistic: 0.9457 on 2 and 40 DF,  p-value: 0.3969

## 
## Call:
## lm(formula = cvlt_1 ~ IS, data = filter(dmem2, Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.1033 -1.3262 -0.2173  1.2568  2.8241 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)    6.860      1.069   6.419  1.7e-07 ***
## IS            -1.037      1.954  -0.530    0.599    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.504 on 37 degrees of freedom
##   (5 observations deleted due to missingness)
## Multiple R-squared:  0.007547,   Adjusted R-squared:  -0.01928 
## F-statistic: 0.2814 on 1 and 37 DF,  p-value: 0.599

## 
## Call:
## lm(formula = cvlt_sdelay_recall ~ IS, data = filter(dmem2, Group == 
##     "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -5.7768 -1.7768  0.3344  2.5294  5.0016 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)   14.168      2.260   6.270 2.71e-07 ***
## IS            -5.560      4.132  -1.346    0.187    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 3.18 on 37 degrees of freedom
##   (5 observations deleted due to missingness)
## Multiple R-squared:  0.04666,    Adjusted R-squared:  0.02089 
## F-statistic: 1.811 on 1 and 37 DF,  p-value: 0.1866

## 
## Call:
## lm(formula = cvlt_ldelay_recall ~ IS, data = filter(dmem2, Group == 
##     "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -8.0911 -2.0285 -0.1671  2.0532  4.7568 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)   13.411      2.105   6.371 1.98e-07 ***
## IS            -3.803      3.849  -0.988     0.33    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 2.962 on 37 degrees of freedom
##   (5 observations deleted due to missingness)
## Multiple R-squared:  0.02571,    Adjusted R-squared:  -0.0006254 
## F-statistic: 0.9763 on 1 and 37 DF,  p-value: 0.3295

## 
## Call:
## lm(formula = cvlt_recognition_hits ~ IS, data = filter(dmem2, 
##     Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.1625 -0.8340  0.3796  1.0134  1.7459 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  16.4211     0.8962  18.323   <2e-16 ***
## IS           -3.0521     1.6388  -1.862   0.0705 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.261 on 37 degrees of freedom
##   (5 observations deleted due to missingness)
## Multiple R-squared:  0.08571,    Adjusted R-squared:  0.061 
## F-statistic: 3.469 on 1 and 37 DF,  p-value: 0.07049

## 
## Call:
## lm(formula = cvlt_1 ~ actphi, data = filter(dmem2, Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.3592 -1.3124 -0.3293  1.5824  2.6479 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)   
## (Intercept)  6.89590    2.36091   2.921  0.00565 **
## actphi      -0.03594    0.16126  -0.223  0.82473   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.481 on 41 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.00121,    Adjusted R-squared:  -0.02315 
## F-statistic: 0.04968 on 1 and 41 DF,  p-value: 0.8247

## 
## Call:
## lm(formula = cvlt_sdelay_recall ~ actphi, data = filter(dmem2, 
##     Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -6.1032 -1.9656  0.5189  2.1995  5.0930 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)   8.4578     5.0963   1.660    0.105
## actphi        0.1920     0.3481   0.552    0.584
## 
## Residual standard error: 3.197 on 41 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.007365,   Adjusted R-squared:  -0.01685 
## F-statistic: 0.3042 on 1 and 41 DF,  p-value: 0.5842

## 
## Call:
## lm(formula = cvlt_ldelay_recall ~ actphi, data = filter(dmem2, 
##     Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -8.3577 -1.9687  0.2576  2.1735  4.8401 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)  
## (Intercept)   8.6903     4.7469   1.831   0.0744 .
## actphi        0.1936     0.3242   0.597   0.5537  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 2.978 on 41 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.008621,   Adjusted R-squared:  -0.01556 
## F-statistic: 0.3565 on 1 and 41 DF,  p-value: 0.5537

## 
## Call:
## lm(formula = cvlt_recognition_hits ~ actphi, data = filter(dmem2, 
##     Group == "Older Adults"))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.8003 -0.8419  0.1619  1.0950  1.3514 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 13.84854    2.04489   6.772 3.46e-08 ***
## actphi       0.06784    0.13967   0.486     0.63    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.283 on 41 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.005721,   Adjusted R-squared:  -0.01853 
## F-statistic: 0.2359 on 1 and 41 DF,  p-value: 0.6298

## 
##  Welch Two Sample t-test
## 
## data:  acc_mean.test by sleepundersix
## t = 0.48569, df = 12.093, p-value = 0.6359
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.06941689  0.10928618
## sample estimates:
##    mean in group Under 6 h mean in group At least 6 h 
##                  0.8638889                  0.8439542

## 
##  Welch Two Sample t-test
## 
## data:  rt_c_mean.test by sleepundersix
## t = -3.4084, df = 24.196, p-value = 0.002291
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -317.24291  -78.00989
## sample estimates:
##    mean in group Under 6 h mean in group At least 6 h 
##                   2612.949                   2810.576

## 
##  Welch Two Sample t-test
## 
## data:  cvlt_ldelay_recall by sleepundersix
## t = 0.2167, df = 13.895, p-value = 0.8316
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -2.185640  2.676549
## sample estimates:
##    mean in group Under 6 h mean in group At least 6 h 
##                   11.70000                   11.45455

## 
##  Welch Two Sample t-test
## 
## data:  cvlt_recognition_hits by sleepundersix
## t = 1.2639, df = 22.027, p-value = 0.2195
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.3028723  1.2483268
## sample estimates:
##    mean in group Under 6 h mean in group At least 6 h 
##                   15.20000                   14.72727

## 
## Call:
## lm(formula = acc_mean.learning ~ sleep_time_mean_sleep * Group, 
##     data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.56251 -0.03620  0.02417  0.10247  0.16240 
## 
## Coefficients:
##                                           Estimate Std. Error t value Pr(>|t|)
## (Intercept)                              8.956e-01  1.431e-01   6.256 1.83e-08
## sleep_time_mean_sleep                    6.723e-07  3.664e-04   0.002    0.999
## GroupOlder Adults                       -2.342e-01  1.755e-01  -1.335    0.186
## sleep_time_mean_sleep:GroupOlder Adults  4.338e-04  4.416e-04   0.983    0.329
##                                            
## (Intercept)                             ***
## sleep_time_mean_sleep                      
## GroupOlder Adults                          
## sleep_time_mean_sleep:GroupOlder Adults    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1384 on 80 degrees of freedom
## Multiple R-squared:  0.08004,    Adjusted R-squared:  0.04554 
## F-statistic:  2.32 on 3 and 80 DF,  p-value: 0.08155

## 
## Call:
## lm(formula = acc_mean.learning ~ sleep_time_mean_sleep + Group, 
##     data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.56547 -0.03944  0.02679  0.09408  0.16274 
## 
## Coefficients:
##                         Estimate Std. Error t value Pr(>|t|)    
## (Intercept)            0.7802345  0.0819040   9.526 7.26e-15 ***
## sleep_time_mean_sleep  0.0002994  0.0002044   1.465   0.1469    
## GroupOlder Adults     -0.0644313  0.0304339  -2.117   0.0373 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1384 on 81 degrees of freedom
## Multiple R-squared:  0.06894,    Adjusted R-squared:  0.04595 
## F-statistic: 2.999 on 2 and 81 DF,  p-value: 0.05541

## 
## Call:
## lm(formula = rt_c_mean.learning ~ sleep_time_mean_sleep * Group, 
##     data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1343.2  -439.7  -102.1   358.2  3854.8 
## 
## Coefficients:
##                                         Estimate Std. Error t value Pr(>|t|)   
## (Intercept)                             2216.583    761.014   2.913  0.00464 **
## sleep_time_mean_sleep                     -1.289      1.948  -0.662  0.50988   
## GroupOlder Adults                        -20.670    932.877  -0.022  0.98238   
## sleep_time_mean_sleep:GroupOlder Adults    1.900      2.347   0.809  0.42066   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 735.9 on 80 degrees of freedom
## Multiple R-squared:  0.2071, Adjusted R-squared:  0.1774 
## F-statistic: 6.965 on 3 and 80 DF,  p-value: 0.0003186

## 
## Call:
## lm(formula = rt_c_mean.learning ~ sleep_time_mean_sleep + Group, 
##     data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1489.3  -417.7   -78.6   317.9  3865.1 
## 
## Coefficients:
##                        Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           1.711e+03  4.346e+02   3.938 0.000173 ***
## sleep_time_mean_sleep 1.889e-02  1.085e+00   0.017 0.986150    
## GroupOlder Adults     7.230e+02  1.615e+02   4.477 2.45e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 734.3 on 81 degrees of freedom
## Multiple R-squared:  0.2006, Adjusted R-squared:  0.1809 
## F-statistic: 10.16 on 2 and 81 DF,  p-value: 0.0001153

## 
## Call:
## lm(formula = acc_mean.test ~ sleep_time_mean_sleep * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.24417 -0.06875  0.01920  0.06881  0.16655 
## 
## Coefficients:
##                                           Estimate Std. Error t value Pr(>|t|)
## (Intercept)                              8.698e-01  1.007e-01   8.636 4.56e-13
## sleep_time_mean_sleep                    9.357e-05  2.578e-04   0.363    0.718
## GroupOlder Adults                       -6.631e-02  1.235e-01  -0.537    0.593
## sleep_time_mean_sleep:GroupOlder Adults  1.811e-05  3.107e-04   0.058    0.954
##                                            
## (Intercept)                             ***
## sleep_time_mean_sleep                      
## GroupOlder Adults                          
## sleep_time_mean_sleep:GroupOlder Adults    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09739 on 80 degrees of freedom
## Multiple R-squared:  0.08914,    Adjusted R-squared:  0.05498 
## F-statistic:  2.61 on 3 and 80 DF,  p-value: 0.05716

## 
## Call:
## lm(formula = acc_mean.test ~ sleep_time_mean_sleep + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.24483 -0.06885  0.01957  0.06902  0.16579 
## 
## Coefficients:
##                        Estimate Std. Error t value Pr(>|t|)    
## (Intercept)            0.864961   0.057281  15.100  < 2e-16 ***
## sleep_time_mean_sleep  0.000106   0.000143   0.742  0.46040    
## GroupOlder Adults     -0.059220   0.021285  -2.782  0.00671 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09679 on 81 degrees of freedom
## Multiple R-squared:  0.0891, Adjusted R-squared:  0.06661 
## F-statistic: 3.962 on 2 and 81 DF,  p-value: 0.02283

## 
## Call:
## lm(formula = rt_c_mean.test ~ sleep_time_mean_sleep * Group, 
##     data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -465.21 -132.18   -2.53  114.82  620.87 
## 
## Coefficients:
##                                          Estimate Std. Error t value Pr(>|t|)
## (Intercept)                             2.442e+03  2.110e+02  11.572   <2e-16
## sleep_time_mean_sleep                   3.004e-03  5.401e-01   0.006    0.996
## GroupOlder Adults                       9.044e+01  2.587e+02   0.350    0.728
## sleep_time_mean_sleep:GroupOlder Adults 5.761e-01  6.509e-01   0.885    0.379
##                                            
## (Intercept)                             ***
## sleep_time_mean_sleep                      
## GroupOlder Adults                          
## sleep_time_mean_sleep:GroupOlder Adults    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 204 on 80 degrees of freedom
## Multiple R-squared:  0.4072, Adjusted R-squared:  0.385 
## F-statistic: 18.32 on 3 and 80 DF,  p-value: 3.862e-09

## 
## Call:
## lm(formula = rt_c_mean.test ~ sleep_time_mean_sleep + Group, 
##     data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -450.65 -135.17  -11.76  109.99  617.05 
## 
## Coefficients:
##                        Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           2288.6427   120.5927  18.978  < 2e-16 ***
## sleep_time_mean_sleep    0.3997     0.3010   1.328    0.188    
## GroupOlder Adults      315.9086    44.8099   7.050  5.4e-10 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 203.8 on 81 degrees of freedom
## Multiple R-squared:  0.4014, Adjusted R-squared:  0.3866 
## F-statistic: 27.16 on 2 and 81 DF,  p-value: 9.435e-10

## 
## Call:
## lm(formula = acc_mean.learning ~ actphi * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.55244 -0.02597  0.03725  0.08182  0.18319 
## 
## Coefficients:
##                           Estimate Std. Error t value Pr(>|t|)    
## (Intercept)               1.123419   0.255790   4.392 3.49e-05 ***
## actphi                   -0.014193   0.015612  -0.909    0.366    
## GroupOlder Adults        -0.135316   0.339867  -0.398    0.692    
## actphi:GroupOlder Adults  0.003776   0.021864   0.173    0.863    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1412 on 78 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.05364,    Adjusted R-squared:  0.01724 
## F-statistic: 1.474 on 3 and 78 DF,  p-value: 0.2282

## 
## Call:
## lm(formula = acc_mean.learning ~ actphi + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.55326 -0.02568  0.03703  0.08378  0.18669 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        1.09201    0.17871   6.110 3.53e-08 ***
## actphi            -0.01227    0.01086  -1.129   0.2622    
## GroupOlder Adults -0.07697    0.03651  -2.108   0.0382 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1403 on 79 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.05328,    Adjusted R-squared:  0.02931 
## F-statistic: 2.223 on 2 and 79 DF,  p-value: 0.115

## 
## Call:
## lm(formula = rt_c_mean.learning ~ actphi * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1365.3  -418.3   -72.4   293.4  3633.9 
## 
## Coefficients:
##                          Estimate Std. Error t value Pr(>|t|)  
## (Intercept)               2659.28    1321.72   2.012   0.0477 *
## actphi                     -57.71      80.67  -0.715   0.4765  
## GroupOlder Adults         1850.66    1756.16   1.054   0.2952  
## actphi:GroupOlder Adults   -84.38     112.97  -0.747   0.4574  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 729.5 on 78 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.2342, Adjusted R-squared:  0.2047 
## F-statistic:  7.95 on 3 and 78 DF,  p-value: 0.0001084

## 
## Call:
## lm(formula = rt_c_mean.learning ~ actphi + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1402.7  -450.9   -65.5   313.7  3701.3 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        3361.34     926.57   3.628 0.000505 ***
## actphi             -100.73      56.32  -1.789 0.077516 .  
## GroupOlder Adults   546.71     189.28   2.888 0.004995 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 727.4 on 79 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.2287, Adjusted R-squared:  0.2092 
## F-statistic: 11.71 on 2 and 79 DF,  p-value: 3.512e-05

## 
## Call:
## lm(formula = acc_mean.test ~ actphi * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.23996 -0.07085  0.02202  0.07274  0.15329 
## 
## Coefficients:
##                           Estimate Std. Error t value Pr(>|t|)    
## (Intercept)               0.965842   0.179133   5.392 7.22e-07 ***
## actphi                   -0.003663   0.010933  -0.335    0.738    
## GroupOlder Adults        -0.102040   0.238013  -0.429    0.669    
## actphi:GroupOlder Adults  0.002611   0.015311   0.170    0.865    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09887 on 78 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.08277,    Adjusted R-squared:  0.04749 
## F-statistic: 2.346 on 3 and 78 DF,  p-value: 0.07919

## 
## Call:
## lm(formula = acc_mean.test ~ actphi + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.23975 -0.07103  0.02459  0.07072  0.15546 
## 
## Coefficients:
##                    Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        0.944122   0.125155   7.544 6.71e-11 ***
## actphi            -0.002332   0.007607  -0.307   0.7600    
## GroupOlder Adults -0.061697   0.025567  -2.413   0.0181 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09826 on 79 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.08243,    Adjusted R-squared:  0.0592 
## F-statistic: 3.548 on 2 and 79 DF,  p-value: 0.03344

## 
## Call:
## lm(formula = rt_c_mean.test ~ actphi * Group, data = dmem2)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -447.6 -116.6   -4.7  120.1  693.5 
## 
## Coefficients:
##                          Estimate Std. Error t value Pr(>|t|)    
## (Intercept)               2764.36     368.07   7.510  8.3e-11 ***
## actphi                     -19.85      22.46  -0.883    0.380    
## GroupOlder Adults          618.13     489.05   1.264    0.210    
## actphi:GroupOlder Adults   -22.54      31.46  -0.716    0.476    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 203.1 on 78 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.421,  Adjusted R-squared:  0.3988 
## F-statistic: 18.91 on 3 and 78 DF,  p-value: 2.599e-09

## 
## Call:
## lm(formula = rt_c_mean.test ~ actphi + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -439.95 -124.73   -4.16  112.14  671.33 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        2951.87     257.96  11.443  < 2e-16 ***
## actphi              -31.34      15.68  -1.999   0.0491 *  
## GroupOlder Adults   269.86      52.70   5.121 2.09e-06 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 202.5 on 79 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.4172, Adjusted R-squared:  0.4025 
## F-statistic: 28.28 on 2 and 79 DF,  p-value: 5.459e-10

## 
## Call:
## lm(formula = acc_mean.learning ~ IS * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.57683 -0.02783  0.03023  0.07388  0.16918 
## 
## Coefficients:
##                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           0.95005    0.09261  10.258 1.17e-15 ***
## IS                   -0.08864    0.21298  -0.416    0.679    
## GroupOlder Adults    -0.11517    0.13304  -0.866    0.390    
## IS:GroupOlder Adults  0.08316    0.27493   0.302    0.763    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.135 on 71 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.08798,    Adjusted R-squared:  0.04944 
## F-statistic: 2.283 on 3 and 71 DF,  p-value: 0.08641

## 
## Call:
## lm(formula = acc_mean.learning ~ IS + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.57826 -0.03125  0.03401  0.08086  0.17598 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        0.92902    0.06079  15.283   <2e-16 ***
## IS                -0.03873    0.13383  -0.289   0.7731    
## GroupOlder Adults -0.07634    0.03461  -2.206   0.0306 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1342 on 72 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.0868, Adjusted R-squared:  0.06144 
## F-statistic: 3.422 on 2 and 72 DF,  p-value: 0.03804

## 
## Call:
## lm(formula = rt_c_mean.learning ~ IS * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1553.7  -434.2   -67.1   297.9  3779.5 
## 
## Coefficients:
##                      Estimate Std. Error t value Pr(>|t|)   
## (Intercept)           1668.26     521.65   3.198  0.00207 **
## IS                      95.32    1199.62   0.079  0.93689   
## GroupOlder Adults     1289.10     749.36   1.720  0.08974 . 
## IS:GroupOlder Adults  -971.49    1548.52  -0.627  0.53243   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 760.6 on 71 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.2234, Adjusted R-squared:  0.1906 
## F-statistic: 6.808 on 3 and 71 DF,  p-value: 0.0004248

## 
## Call:
## lm(formula = rt_c_mean.learning ~ IS + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1547.7  -412.6   -62.1   317.0  3797.1 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)         1914.0      343.1   5.578 4.01e-07 ***
## IS                  -487.7      755.4  -0.646    0.521    
## GroupOlder Adults    835.4      195.3   4.276 5.74e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 757.4 on 72 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.2191, Adjusted R-squared:  0.1974 
## F-statistic:  10.1 on 2 and 72 DF,  p-value: 0.000136

## 
## Call:
## lm(formula = acc_mean.test ~ IS * Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.24823 -0.06037  0.02654  0.06488  0.17941 
## 
## Coefficients:
##                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           0.92182    0.06631  13.901   <2e-16 ***
## IS                   -0.01505    0.15250  -0.099    0.922    
## GroupOlder Adults    -0.12550    0.09526  -1.317    0.192    
## IS:GroupOlder Adults  0.10492    0.19686   0.533    0.596    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.0967 on 71 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.1299, Adjusted R-squared:  0.09318 
## F-statistic: 3.535 on 3 and 71 DF,  p-value: 0.01898

## 
## Call:
## lm(formula = acc_mean.test ~ IS + Group, data = dmem2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.25066 -0.05939  0.02616  0.06746  0.16828 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        0.89529    0.04359  20.541  < 2e-16 ***
## IS                 0.04791    0.09595   0.499  0.61908    
## GroupOlder Adults -0.07650    0.02481  -3.083  0.00291 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.09621 on 72 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.1265, Adjusted R-squared:  0.1022 
## F-statistic: 5.212 on 2 and 72 DF,  p-value: 0.007694

## 
## Call:
## lm(formula = rt_c_mean.test ~ IS * Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -426.24 -123.89  -24.89  121.07  597.08 
## 
## Coefficients:
##                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           2447.85     146.51  16.707   <2e-16 ***
## IS                     -52.79     336.94  -0.157    0.876    
## GroupOlder Adults      228.60     210.47   1.086    0.281    
## IS:GroupOlder Adults   223.42     434.93   0.514    0.609    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 213.6 on 71 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.4049, Adjusted R-squared:  0.3798 
## F-statistic:  16.1 on 3 and 71 DF,  p-value: 4.387e-08

## 
## Call:
## lm(formula = rt_c_mean.test ~ IS + Group, data = dmem2)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -423.15 -123.04  -14.88  128.27  601.95 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        2391.34      96.28  24.836  < 2e-16 ***
## IS                   81.29     211.97   0.383    0.702    
## GroupOlder Adults   332.95      54.82   6.074 5.34e-08 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 212.5 on 72 degrees of freedom
##   (9 observations deleted due to missingness)
## Multiple R-squared:  0.4027, Adjusted R-squared:  0.3861 
## F-statistic: 24.27 on 2 and 72 DF,  p-value: 8.774e-09